Oil level gauge



E, R. WILSON v OIL LEVEL GAUGE May 1, 1951 Filed Oct. 16, 1947 PatentedMay 1, 1 951 OIL LEVEL GAUGE Earl R. Wilson, Flint, Mich, a'ssignor toGeneral Motors Corporation, Detroit, Mich, a corporation of DelawareApplication October 16, 1947, Serial No, 780,243

This invention relates to a detail improvement in dip sticks, such asare used to measure oil level in an engine crankcase. Motor trucks re-vcently placed in production have the front end sheet metal so designedthat the wheel fenders are relatively high with respect to engineposition so as to make unhandy access to the gauge rod as heretoforearranged.

To meet the situation the access opening in the crankcase for removablereception of the usual dip stick has been provided with an upstandingextension tube for supporting a much longer ullage rod, whose upperterminal handle is within convenient reach when the engine hood israised.

The added rod length makes the rod more susceptible. to breakage and tovibration fatigue failure if the conventional rod is merely in?- creasedin length below the Ordinary friction sprin retainer by which it wouldbe supported only at the upper end of the extension tube with the lowerunsupported free end projected a considerable distance downwardly intothe liquid and subjected to long leverage whipping tendency,

To minimize whipping for projected unsupported length is one of theobjects Of this invention and particularly an object is to provid a moresimple, easier formed and less expensive single piece rod which will bedurable in use and quick.-

ly and conveniently removable and then replace able in a long extensiontube and snugly fitted thereto mainly in the final stage of homepositioning.

In a preferred embodiment of the invention the intermediate portion ofthe rod to be housed within the extension tube has integral deformationsto fit the tube wall under slight stress and preferably throughout mostof the length of the tube so as to have substantial area of supportinglongitudinal contact with the tube and to engage near both of the widelyspaced apart tube eX- tremities for a stable mounting. More specificallythe deformations integral with the intermediate mounting portion of therod consist of a series of longitudinally spaced lateral offsetsalternating in opposite directions and which can be conveniently coinedbetween dies in a single stroke. It is to be noted that in anarrangement of three successive ofisets the dimensioning can be suchthat a snug friction fit with the tube walls occurs only when all threeoffset seating sections are housed. Within the tube. Thus upon insertionthe rod can be dropped downwardly by its own weight except in the finalshort length of axial travel when an added Push will be required as 8Claims. (01. 33--1 26.7)

the uppermost offset enters the tube and causes all three onsets tofrictionally engage the tubewalls and similarly upon removal a greaterpull is needed to overcome friction sliding contact of the three offsetsonly in the initial short length upward lift until the uppermost offsetclears the top of the extended mounting tube. Consequently, the effortrequired to manipulate the rod corresponds to that with the conventionalshort length gauge rod but a much longer range of friction bearing orseating in the home position is afforded by the cooperation of the rodand extension tube for resisting displacement and increasing rodstiffness.

A better understanding of the structure will be had upon inspection ofthe accompanying drawing wherein Figure l is a front elevation withparts broken away of a motor vehicle embodying the invention; Figure 2is an enlarged frag.- ment corresponding to the showing of Figure l andwith parts in section and Figure 3 is a perspective view showing themounting tube in section and the corrugated intermediate portion of thegauge rod fitted to the tube.

Figure 1 illustrates the position of the engine I between and inrelation to the very high sheet metal fenders 2.-2 over the frontwheels. When the engine cover or hood 3 is lifted for inspection orreplenishment of the oil supply the depth of the engine makes it ratherinaccessible from above the top of the fenders and accordingly theconventional filler tube 4 is shown provided with a supplementary oradapter tube section 5 pro jected upwardly and secured by a split clamp53.

' As usual the side wall of the engine crankcase is provided with ahollow boss 7 for the reception of an oil level stick. In the presentinstance there is press fitted within the hollow boss the lower end ofan upstanding extension tube 8 terminating at a more convenient heightin relation to the top of the wheel fender 2.

The dip stick, to be received within the mount.- ing tube 8, will needto be of unusual length in order that the opposite terminals willproject downwardly into the crankcase oil and upwardly within convenientreach for manual manipulation from the top of the engine compartment.For example, an overall length of slightly more than two feet has beenprescribed for a commercial embodiment. Circular rod stock of coldrolled steel has been selected from which to produce the gauge and asusual the lower end portion. 9 terminates in a flattened length andcontains markingfi .or inclicia to facilitate reading of the liquidlevel by reason of the lubricating oil clinging thereto and uponwithdrawal of the rod for inspection. The upper end Ill of the rod,which may project quite a bit beyond the top of the extension tube 8,preferably terminates in a curled eye or the like for handling purposes.A stop washer or disk II is secured on the handle portion H] by means ofstaking for engagement with the top of the extension tube 8 for fixingthe depth to which the lower end of the rod can extend into the liquidreservoir. If desired a felt washer, not shown, may cover the undersideof the stop washer I! for sealing the contact with the end of the tube.Throughout its intermediate portion, which is to be housed within themounting tube 8, the rod has a series of friction seating portionspressed outwardly in different directions and soformed as to provide aslight degree of springiness o-r flexibility which insures a snug fitand also eliminates need for extreme accuracy in manufacture. Three ofsuch offsets are shown in the drawing in longitudinally spaced relationto each other as at 12, E3 and Hi. These are formed by a coiningoperation so that the round section stock at spaced intervals isdeformed to a substantially D-shape in cross section providing anarcuate peripheral surface corresponding somewhat to the internalcircular outline of the tube 8. Each offset will extend on a straightline for a distance of one-half inch or thereabouts and will beconnected at opopsite ends by inwardly sweeping or inclined portionswith the round cross sectional portions of the rod. With theintermediate ofiset l3 pressed in opposite direction to the endmostoffsets l2 and i i a zigzag intermediate length of the rod will providefor a sliding frictional engagement at three places between the ;rod andtub By properly dimensioning the parts to insure a close fit there willbe a certain .strain on the parts in their normal relation which willassist in stabilizing the opposite free ends of the rod againstvibration flutter. The lengths of the offsets and the longitudinalspacing between them shouldbe such that the endmost offsets l2 .and idengage with the tube fairly close to the -.opposite ends of the tube totake greatest advanztage to the mutual stifiening available. It will be'noted particularly that when the rod is to be withdrawn the first stageof its pull will be upwardly until the offset l2 clears the top of thetube, after which the ofisets l3 and it nolonger will provide a closebinding slip fit on the interior of the tube 8 and the furtherwithdrawal of the tube can be accomplished by merely lifting the weightof the stick directly upwardly. The path of movement of the handle endof the dip stick can be somewhat as illustrated by the broken lines inFigure 1 where it will be appreciated that a conveniently normalmovement is provided for to remove the dip stick and bring it out of theengine compartment for easy inspection. Replacement of the gauge will,of course, be just as easily accomplished and in the final stage ofmovement as the offset [2 enters the top of the tube 8 a slightlyincreased push will move the stop washer I I home and assure a firmretention of the gauge rod in the engine crankcase.

I claim:

1. For measuring liquid depth in a sump which is inaccessibly located, arelatively long rod having one terminal portion insertable and removablethrough an opening in the sump wall for projection into the liquid, anopposite terminal portion to project upwardly for ready handlingaccessibility and an intermediate mounting portion, a rod mounting tubeprojecting upwardly from the sump wall opening to receive said rod toafford a supporting portion for said intermediate mounting portion, oneof the last two mentioned portions having a series of lateral oflsetssuccessively longitudinally spaced from one another for frictionalengagement with the other of said last two mentioned portions, saidoffsets projecting alternately in opposite directions and being soarranged that close frictional engagement of the rod and tube isobtained only when more than two of said longitudinally spaced offsetsare engaged with said other of the last two mentioned portions.

2. In a device of the character described, a liquid sump having anopening in the wall thereof, a tube portion mounted to project upwardlyfrom said opening, a gauge rod having a level indicating lower portionand an intermediate mounting portion projected through said tubeportion, one of the last two mentioned portions having a series oflongitudinally spaced lateral offsets, the endmost of which offsets arein substantially axial alignment and at least one other of which offsetsintermediate and longitudinally spaced from the endmost offsets is outof axial alignment and substantially diametrically opposed thereto sothat the several ofisets cooperate to aiford easy introduction but aclose fitting frictional contact between the rod and tube.

3. In combination, a liquid container having an opening to receive a dipstick, an extension tube projected upwardly from said opening, and a dipstick removably mounted in said tube, said stick being characterized bya longitudinally spaced succession of lateral projections in undulatoryformation for frictional bearing engagement with longitudinally spacedportions of the tube alternately on opposite sides thereof and nearopposite ends of the tube.

4. In the structure of claim 3, said lateral projections being integraloffset deformations in the dip stick.

5. A level gauge dip stick having an upper handle portion, a lower levelindicating portion and an intermediate mounting portion, said mountingportion having sinuous oifset corrugations affording frictiona-L bearingseats integral therewith and arranged in longitudinal spaced relation,said longitudinally spaced seats being successively projected laterallyin alternate back and forth relation across the axis of said mountingportion.

6. An ullage rod for detachable retention within a rod mounting receiverof a liquid reservoir, said rod terminating in a level gauge portion andhaving a mounting portion comprising three longitudinally spaced andlaterally offset friction bearing seats integrally formed therein andwith the centrally ofiset seat projected in the direction opposite tothat of the two endmost seating offsets.

7. A level gauge dip stick comprising an upper handle portion and amounting portion having a plurality of laterally bent offset frictionalbearing seats each of substantial length measured axially of saidmounting portion, said seats being positioned in longitudinal spacedrelation and being successively projected laterally in alternate backand forth relation across the longitudinal axis of said mountingportion.

8. Apparatus of the character claimed in claim 7, wherein each seatfaces in the opposite direc- 5 tion from the next adjacent seat, and inwhich the length of each seat is several times the width file of thispatent:

6 UNITED STATES PATENTS Number Name Date thereof.

v 971,480 Wegner Sept. 27, 1910 EARL WILSON 5 1,658,774 Taub Feb. 7,1928 CITED 1,681,431 Pribil Aug. 21, 1928 1,865,285 Spencer June 28,1932 The followmg references are of record 1n the 1,981,270 Honingsworth20, 1934

